1. Field of the Invention
The present invention relates to a vapor drying method, an apparatus and a recording medium for use in the method.
2. Background Art
In the past, the IPA drying technology has been known, which comprises the steps of vaporizing a mixed fluid containing fluids including a liquid(s) or liquid fluid(s), for example, a fluid prepared by mixing an atomized organic solvent, e.g., IPA (isopropyl alcohol), in an inert gas such as nitrogen gas (N2 gas), and then making the vaporized gas contact with an article(s) to be processed (article(s) to be dried) to dry the article (see, for example, Patent Document 1).
According to the vapor drying method (or apparatus), after effecting a first drying step in which vapor comprising IPA and N2 gas is supplied to a processing chamber containing an article(s) for example a semiconductor wafer(s) (hereinafter referred to as wafer(s)), a second drying step in which only N2 gas is supplied to the processing chamber to vaporize and remove IPA attached to the wafer(s) can be performed.
Document cited:
Patent Document 1: TOKUKAIHEI No. 10-125649
However, in the conventional vapor drying method (or apparatus) of this type, because of heating after mixing IPA and N2 gas by using a mixing means, the flow amount of N2 gas possible to flow into the mixing means is restricted due to an optimum range of the proportion in mixing the IPA and N2 gas. In the case where the second drying step is performed successively after the first drying step, N2 gas is supplied to the processing chamber by supplying only the N2 gas to the mixing means.
In such a way, since the flow amount of N2 gas possible to supply to the mixing means is set in a range which is optimum for mixing IPA, this flow amount should be restricted. Thus, when N2 gas is used in the second drying step, because of the smaller supply amount, the time required for the second drying step should be increased, leading to an adverse effect on the drying ability, such as occurrence of water marks. In addition, supplying a smaller amount of the inert gas for a rather long period of time may lead to considerable waste of the inert gas.